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Matt,
It is unfortunate that the cam bearings often de-laminate and need to be replaced. Be sure to use the "wide-style" bearings (the narrow replacement bearing is likely to spin in the block). Onanparts.com has a kit with front and rear bearings and the cam Welch plug for about $40, and Boomer may have the same items. Do not buy the bearing set until everything is measured, and you are sure there are no other surprises with wear on the connecting rod caps, pistons, etc. Installing the new bearings is tricky and is best done by cooling the bearing and driver tool on dry ice.

Have you been able to remove the crank gear? You may be aware that a bit of heat is required. With a puller attached, carefully hit just the gear with a propane torch. Installing the gear is best done by heating the gear to about 450 degree F (in an oven, when the cook happens to be out of the house). So, that is the kind of heat needed to remove the bearing--a bit hotter than boiling water, but not the kind of heat needed to remove a rusty bolt from a wagon frame.
Harold
 

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Discussion Starter #84
Harold I will try to get some measurements to see if things are in spec. Does someone have list easily accessible that I should check at this juncture?
The Welch plug is the 9/16 bolt with spring under it? I took it out and looked at it cleaned sprayed fluid through port. My question Is what does it do and what wears on it?
I have not been able to attempt the crank gear yet. The picture a few posts ahead seems to be like the best method but that plate would have to have exact hole size to slide over shaft and yet leave 10/32 holes exposed. I don't have a plate like that yet. I have plate type puller with tapered bolt in middle but that would only go on end of crank it would be 3 inches to threaded holes.
Chuck the journals are smooth but the one on end away from gear does"step up" is that normal or worn? I can get a picture. Thanks Matt.
 

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The 9/16" bolt with the spring under it is the oil pressure regulator. There should also be a small piece under the spring.
The welch plug is the 1 1/2" (about) almost flat cover for the camshaft . It fits into the "step" you mentioned.
 

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I think the "step up" he's referring to is the lobe on the cam that opens the points on the non-electronic ignition engines.
 

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Here is a picture of a good used cam as posted on Onanparts.com -- you can readily see the step on the right end of this view. Sometimes a picture is helpful in saving a bunch of words of description...

262691


Chuck
 

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Discussion Starter #88
Yep I'll get a picture of mine tonight when I get home from work. That's the step I was mentioning.
 

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Discussion Starter #90
If I was gonna have one of those plates made to pull the gear does anyone know the exact size diameter of the center hole to go over the shaft seems like it's close to inch and a 1/2
 

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Matt, Go to Lowe's or Harbor Freight and get a pair of calipers. They usually run about $20 and will save you the time of waiting for an answer here! Bob
 

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Discussion Starter #92
Gotcha. And is it bad if the plate doesn't totally bottom out against gear? Using grade 8 bolts and there ended up being slight gap between plate and gear.
 

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I'm not familiar with your engine, Matt, But I DO see something protruding from the back of the gear...some type of ACR or timing advance ??? I'd say, No, plate needs to touch gear." Maybe lay maybe eight 3/8" nuts on plate and have gear sit on nuts so you clear protrusions. You want to pull on gear, nothing else. Bob
 

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Discussion Starter #94
Bommer not a fan of 3 stone deglazer what size and grit ball hone should I get to attempt a good cross hatch? Thinking of buying or borrowing one. Any ideas on site to buy one? Thanks.
 

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Discussion Starter #95
And tomorrow is the big day I had my buddy that makes the 80 tailgates make me a 3 1/2 round plate with 1 1/2 hole in middle. 3/8 steel, bought 2 grade 8 bolts and will attempt the crank gear removal.
 

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Discussion Starter #97
I don't see much info or video on removing crank bearing? Does it also just drive out? And do you always replace it when your this far? Always bad?
 

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In my experience or opinion these main bearings are usually okay, but not always. Manual says new tolerance is .0025-.0038", with a wear tolerance of .0057". I can't measure that accurately, but expect that some people can. Another way to measure clearance is with a dial indicator, with the crankshaft back in the block and the bearing plate on at the other end. Then see how much the crankshaft can be moved side to side in the bearing. How are the main journals on the crankshaft? On the main journals, wear often shows up as a raised ridge in the center, where the bearing has a gap for the oil.
 

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Matt, You're this far into the engine, just replace it BUT after getting measurements on crankshaft journals.

Jumping ahead here, make sure you pre-lube the bearings and crank journals when re-assembling. I don't know what's available now, but I always used STP for pre-lube. Bob
 
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